Please check the order of my basic skincare routine to improve my skin tone.

My skin has been looking a lot dull lately, so I'm thinking about drastically revamping my overall skincare routine. Currently, my routine consists of just applying a moisturizing cream after cleansing, but I was wondering if adding a whitening ampoule or retinol product would work. What order should I place these products in, morning and evening, to create a synergistic skincare routine? I'm worried that over-nutrition might actually cause breakouts, so I'm curious about how to structure a skincare routine that maintains a healthy oil-moisture balance. If you have any skincare routine combinations or step-by-step tips that have proven effective, please let me know. Could you please share some helpful skincare routine guides?